There are more than 80 autoimmune conditions (lupus, rheumatoid arthritis, coeliac disease, and multiple sclerosis are a few), but they have one thing in common: inflammation.
“In general, autoimmune diseases manifest and cause symptoms and problems in various organs because of the inflammation that’s associated with them,” says rheumatologist Dr Zachary Wallace, a specialist in autoimmune and inflammatory conditions. So while not all inflammation involves an autoimmune illness, autoimmune illness generally involves inflammation.
An illness is classified as autoimmune when cells and other immune system components, instead of saving their firepower for invading bacteria or viruses, attack parts of the body, leading to symptoms.
With some autoimmune conditions, inflammation happens right at the start, setting the stage for later problems. For example, in type 1 diabetes, inflammation destroys beta cells in the pancreas, which keeps them from making the insulin needed to store sugar from carbs. Sjögren’s syndrome begins when inflammation damages exocrine glands (those that make tears and saliva), leading to severe dryness in the eyes and mouth.
In other autoimmune illnesses, ongoing inflammation is a hallmark symptom. Rheumatoid arthritis (RA) is marked by hot, inflamed joints, while inflammation in the digestive tract in someone with ulcerative colitis may cause significant abdominal pain and bloody diarrhoea. With multiple sclerosis, inflammation settles in the central nervous system after immune cells attack the coating on nerves; while lupus can cause inflammation in the heart, brain, kidney, and other organs. “By definition, ‘autoimmune’ is a problem with inflammation,” says rheumatologist Dr Michael Kaplan.
What causes autoimmune disorders?
Researchers are trying to suss this out, but so far they aren’t completely sure. When the immune system acts as it should and viruses, bacteria, or other substances make their way in – say, through the skin, mouth, or lungs – the immune system prompts cells to make antibodies targeting the invaders.
The immune system is supposed to inspect the cells it makes, with any that don’t behave properly being isolated and destroyed, but in some people that demolition fails to happen and those problematic antibodies attack healthy body parts instead, leading to autoimmune disease and inflammation, Dr Wallace says.
Genetic predisposition may partly explain many autoimmune problems, but it is not the whole picture; not everyone with the same gene ultimately gets a disease. Once someone is genetically susceptible, it may take an environmental exposure to trigger a condition. That might be smoking (a prime risk factor for RA), chemical toxins, or a viral infection (researchers are watching closely to see whether COVID might cause some autoimmune diseases). Since a majority of auto-immune patients are female, hormones and sex-specific factors likely also play a role in some conditions.
The future of treating autoimmune issues
Doctors hope treatments that actually reset the immune system, curing the illness, might one day become available. For now, though, therapies for autoimmune conditions primarily serve to tamp down inflammation. For decades that has meant steroids, which are “the best drugs and the worst drugs,” as Dr Kaplan puts it, because they work well and fast but have numerous serious side effects. Rheumatologists do their best to try to minimise the dosage of steroids by adding other medications.
Biologic drugs such as Humira, Remicade and Enbrel have been game changers; they stop the secretion of a substance that tells other cells to ramp up inflammation, reducing symptoms, such as joint pain in the case of RA.
More recent drugs go after various mechanisms involved in creating unwanted inflammation. “Each autoimmune disease causes inflammation through a different pathway. Depending on which pathway we are trying to control, that’s the medication we use,” saysrheumatologist Dr Juan Maya-Villamizar.
In addition to these powerful meds, other therapies can help. People with autoimmune diseases still suffer from pain and other symptoms, but today treatments and ongoing research are light-years ahead of where they were a few decades ago. “This is a very exciting time,” Dr Wallace says. “There are a lot of new therapies on the horizon.”
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